Resilient seat and platform assembly



United States Patent inventor Edward C. Levit Grand Rapids, Mich. Appl. No. 792,951 Filed Jan. 22, 1969 Patented Dec. 29, 1970 Assignee Steelcase, Inc.

Grand Rapids, Mich. a corporation of Michigan RESILIENT SEAT AND PLATFORM ASSEMBLY 7 Claims, 5 Drawing Figs.

US. Cl a. 267/110, 267/105, 267/111 Int. Cl. F16f 3/00, F16f 3/02 Field of Search 267/80, 103, 105,110,111

References Cited UNlTED STATES PATENTS 2,860,693 1 H1958 Riebel 267/] I0 3,165.308 1/1965 Rathbun 267/111 FOREIGN PATENTS 356,995 9/1931 Great Britain 267/1 10 Primary Examiner-Arthur L. La Point Assistant Examiner-Howard Beltran Attorney-Price. Heneveld, Huizenga and Cooper ABSTRACT: A resilient seat platform comprising a plurality of individual spring units resting on a metal seat frame. Each of said spring units consists first of a flexible metal strap, having a hole near each of its two ends, which is bent gradually over to form a small loop such that said holes are disposed underneath the rest of said strap. The ends of a slightly curved, flexible metal bar, slightly longer than the strap, fit through said holes underneath said strap and rest against said strap within the loops at the ends thereof. The bar portion of said spring unit fits near its ends into two notches or grooves which are directly opposite each other on two opposite sides of a metal seat frame. The ends or looped portions of said metal strap of said spring unit rest on the surfaces of said opposite sides of said seat frame.

PATENTEUnEmmm I I 3,

INVENTOR. 20 010 400 c. 48107 B gw BACKGROUND OF'Tl-IE INVENTION In seat construction, a cushion is generally placed on some sort of seat platform. This platform is preferably resilient in order to compliment the resiliency of the seat cushion.

Ideally, the resilient seat platform, like theseat cushion, should respond only to the load placed directly above it. In this way, the buttocks of the person setting on the seat are supported at all points; and, the person's body weight is distributed over a large area .of his buttocks.

However, in prior devices such as that disclosed in US. Pat. No. 3,165,308 the flexible elements of the seat platform are generally tied to each other in some way in order to hold them in relatively fixed positionsrwith respect to each other. The result is that a persons entire weight is supported by a smaller portion of his buttocks than would be desirable. This effect creates a more board like platform than would be the ideally desired.

Further, a seat platform of this type is generally a combination of flexible spring units mounted onto a seat frame and tied together so they dont move out of place with respect to each other. Such construction requires the complete assembly of the spring units with the seat frame before the construction of the seating article such as a chair or sofa, requiring expensive and costly manufacturing apparatus, machinery, jigs, dies, and labor. In addition, the resultant seat platform is difficult and costly to ship and store.

The object of this invention is to provide a seat platform which would be less boardlike, less costly to construct, and easier and less costly to ship and store.

SUM MARY This invention provides a resilient seat platform comprising a plurality of individual flexible spring units, each having two ends, mounted on a seat frame such that each of said ends of each of said individual spring units is free to move with respect to saidse at frame and independently of the other of said spring units.

Thus, in this seat platform, the individually responding spring units are not tied to the response of other spring units. This gives the seat platform a less board like response to the weight ofa person using the seat.

This seat platform is easy and inexpensive to assemble. In this invention, it is not necessary to assemble all of the individual spring units into a single entity before mounting them on the chair frame. Each spring unit is individually placed on the seat frame. Thus, the manufacturing step of combining the individual spring units into a single entity before mounting them on the seat frame is eliminated. Further, the individual spring units, and frames are easier and less costly to ship and store.

DRAWINGS thereto.

FIG. 4 is a plan view of the seat frame. FIG.'5 is a side elevational view-of an individual spring unit in compression with the seat frame shown and with the original or uncompressed position of the spring unit shown in phantom. v

PREFERRED EMBODIMENT Referring to FIG. 1, it can be seen that the basic elements of the invention are a plurality of individual and independent flexible spring units 10 mounted on a seat frame 20. Referring to FIG. 3, it can be seen that each individual spring unit 10 consists of a flexible metal strap 30 in combination with a flexible curved metal bar 40. The nature of these individual elements and their combination will be described in more detail hereinafter.

The seat frame 20 is preferably constructed of a heavy gauge steel. It is either square or rectangular depending on the ultimate design of the chair or couch and has a front and rear side 21a and b and a left and right side 22a and b. Each of the four sides 21a and b and 22 a and b are .U"-shaped and thus include an upper leg 23 and lower leg 24 connected together by a bight portion 25. For economic reasons, the lower leg 24 can be shorter than. the upper leg 23. As will be seen later,

upper leg 23 must be sufficiently tall to provide support for the spring units 10 when they are in compression.

As would be expected, the front and rear sides 21a and b and left and right sides 22a and b of the seat frame 20 correspond to the front and rear sides and left and right sides of the completed chair. In the top legs. 23 of the left and right sides 22a and b of the seat frame 20 there are an equal number of notches or grooves 26. Furthermore, these notches 26 are directly opposite each other such that a line drawn between any two opposite notches 26 would be parallel to both the front and rear sides 21a and b Each of the several individual spring units 10 comprises first a flexible metal strap 30. This strap is preferably about an inch and a quarter wide and is slightly longer than the distance between the left and right sides 22a and b of the seat frame 20. Near each of the two ends of the flexible strap 30 is a cut out or punched hole "31. The ends of the strap 30 are gradually bent over to form a loop 32 such that each of the holes 31 is disposed on the underside ofthe rest of the strap 30. This construction is best illustrated in FIG. 2.

The other element of each individual spring unit 10 is a flexible metal bar 40 having two ends 41. This bar 40 is slightly longer than the flexible strap 30 having looped ends 32, and it is slightly curved.

The ends 41 of the flexible bar 40 flt through the holes 31 of the flexible metal strap 30 and rest against the flexible metal strap 30 within the looped portions 32 of the flexible metal strap 30. The flexible metal strap 30 and the flexible curved bar .40 so combined constitute an individual flexible spring unit 10.

Each such spring unit 10 rests on the seat frame 20 such that one of its ends rests on the upper leg 23 of the left side 22a of the seat frame 20, and the other end of the spring unit 10 rests on the upper leg 23 of the right side 22b. Each spring unit 10 is preferably parallel to the front and rear sides2la and b of the seat frame 20 and is held in position on the seat frame 20 by means of the flexible bar portion 40 of the seat frame 10 being seated in or passing through a pair of notches 26 disposed opposite each other in the upper legs 23 of the left and right sides 22a and b. The looped portions 32 of each spring unit 10 rests on the upper legs 23 of the left and right sides 22a and b respectively as is best illustrated in F IG. 3 of the drawings.

FIG. 5 shows what happens to an individual spring unit when it is placed in compression by a person sitting on the completed chair. The flexible metal strap 30 flexes in a downward direction. The flexible metal bar 40 also bows in a downward direction. This flexing is made possible because the looped portions 32 of the flexible metal strap 30 are free to slide longitudinally inwardly of itself and laterally with respect to the sides 22 on the top surfaces of legs 23 of the left and right sides 22a and b of the seat frame 20. When the compressingforce is removed from the chair, the looped portions 32 of the'flexible strap 30 slide longitudinally outwardly of itself and laterally with respect to the sides 22 on the top surfaces of legs 23 of the left and right sides 22a and b because of the force exerted by the flexible bar 40 returning to its original position. Thus, the entire spring unit returns to its original position on the seat frame as is indicated in phantom in FIG. 5.

As can be seen from FIG. 1, each ofthe spring units It) acts individually. None of the spring units 10 are tied together. Furthermore, their motion is not tied or restricted by the seat frame 20 except for the fact that the seat frame 20 gives them vertical support, and they cannot move laterally with respect to each other because of the grooves 26. Thus, each spring unit 10 responds only to the load placed directly above it. No load placed on a spring unit 10 is transferred in any way to any of the other spring units 10.

Furthermore, it will be seen that the necessity of tying the spring units 10 into a single entity in order to hold them in their parallel relationship to one another has been eliminated. The notches 26 in the seat frame 20 have given the seat frame 20 and additional functional value to the seat frame in the completed chair. It is the notches 26 in the seat frame 20 which hold the individual spring units 10 in positions parallel to each other, or in other words prevents them from moving laterally with respect to each other.

Finally, because the spring units 10 do not have to be tied together, they can be stored and shipped much more compactly. They can be stored and packaged in roughly one-half the space of a comparable unit wherein they have to be tied together.

Thus, this invention provides both a less expensive resilient seat platform and a less boardlike resilient seat platform.

It is understood that the above description is a preferred embodiment of this invention and that many different modifications and forms can be made thereof without departing from the broader aspects thereof.

lclaim:

l. A resilient seat platform comprising: a seat frame having at least two oppositely disposed sides, said two oppositely disposed sides having equal numbers of oppositely disposed notches; a plurality of independent flexible spring units, each having two ends; each of said spring units comprising a nonelastic, flexible strap having two ends and a slightly flexible, slightly curved bar having two ends being joined to said two ends of said flexible strap; each of said independent spring units being individually seated in a pair of said oppositely disposed notches, said flexible bar passing through said notches; said two ends of each of said spring units being free to slide longitudinally with respect to each other and laterally with respect to said two oppositely disposed sides.

2. A resilient seat platform comprising: a plurality of individual elongated. flexible spring units, each having two ends. mounted on a seat frame having a plurality of sides, said ends of each of said spring units resting on one of different opposite sides of said seat frame; each of said ends of each of said spring units being free to individually move longitudinally of itself and laterally with respect to said sides of said seat frame and independently of the other of said spring units; and means for restraining the movement of each of said spring units in a direction laterally of itself and longitudinally of said sides of said seat frame.

3. A resilient seat platform as in claim 2 wherein each of said individual flexible spring units comprises a flexible strap having two ends and a flexible, slightly curved bar having two ends; said flexible strap being joined at its said two ends to said two ends of said flexible, slightly curved bar.

4. A resilient seat platform as in claim 3 wherein the means for restraining includes grooves in each of said different opposite sides of said seat frame, in which grooves are seated a flexible bar of one of said flexible spring units.

5. A resilient seat platform as in claim 2 wherein each of said individual flexible spring units comprises a flexible strap having two ends and a flexible, slightly curved bar having two ends; said flexible strap having a hole near each of its said two ends and said flexible strap being bent gradually over near eachof its said two ends to form a loop thereat such that said hole 15 disposed on the underside of said loop; each of said two 

